Both warning and warning-message are pretty low on questions, and both cover practically identical area. I don't have enough points (whatever they are) to propose synonym myself, so posting here.
1 Answer
Instead of making the two tags synonym, I have deleted them, since I agree with MPD.
I don't think we have users who answer questions about warning messages, and just to those questions. The fact then that some code is causing an warning message is not so relevant for answering to need its own tag.